zephyr/doc/develop/optimizations/tools.rst

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.. _optimization_tools:
Optimization Tools
##################
The available optimization tools let you analyse :ref:`footprint_tools`
and :ref:`data_structures` using different build system targets.
.. _footprint_tools:
Footprint and Memory Usage
**************************
The build system offers 3 targets to view and analyse RAM, ROM and stack usage
in generated images. The tools run on the final image and give information
about size of symbols and code being used in both RAM and ROM. Additionally,
with features available through the compiler, we can also generate worst-case
stack usage analysis.
Some of the tools mentioned in this section are organizing their output based
on the physical organization of the symbols. As some symbols might be external
to the project's tree structure, or might lack metadata needed to display them
by name, the following top-level containers are used to group such symbols:
* Hidden - The RAM and ROM reports list all processing symbols with no matching
mapped files in the Hidden category.
This means that the file for the listed symbol was not added to the metadata file,
was empty, or was undefined. The tool was unable to get the name
of the function for the given symbol nor identify where it comes from.
* No paths - The RAM and ROM reports list all processing symbols with relative paths
in the No paths category.
This means that the listed symbols cannot be placed in the tree structure
of the report at an absolute path under one specific file. The tool was able
to get the name of the function, but it was unable to identify where it comes from.
.. note::
You can have multiple cases of the same function, and the No paths category
will list the sum of these in one entry.
Build Target: ram_report
========================
List all compiled objects and their RAM usage in a tabular form with bytes
per symbol and the percentage it uses. The data is grouped based on the file
system location of the object in the tree and the file containing the symbol.
Use the ``ram_report`` target with your board, as in the following example.
.. zephyr-app-commands::
:tool: all
:app: samples/hello_world
:board: reel_board
:goals: ram_report
These commands will generate something similar to the output below::
Path Size %
========================================================================================
Root 4637 100.00%
├── (hidden) 4 0.09%
├── (no paths) 2748 59.26%
│ ├── _cpus_active 4 0.09%
│ ├── _kernel 32 0.69%
│ ├── _sw_isr_table 384 8.28%
│ ├── cli.1 16 0.35%
│ ├── on.2 4 0.09%
│ ├── poll_out_lock.0 4 0.09%
│ ├── z_idle_threads 128 2.76%
│ ├── z_interrupt_stacks 2048 44.17%
│ └── z_main_thread 128 2.76%
├── WORKSPACE 184 3.97%
│ └── modules 184 3.97%
│ └── hal 184 3.97%
│ └── nordic 184 3.97%
│ └── nrfx 184 3.97%
│ └── drivers 184 3.97%
│ └── src 184 3.97%
│ ├── nrfx_clock.c 8 0.17%
│ │ └── m_clock_cb 8 0.17%
│ ├── nrfx_gpiote.c 132 2.85%
│ │ └── m_cb 132 2.85%
│ ├── nrfx_ppi.c 4 0.09%
│ │ └── m_channels_allocated 4 0.09%
│ └── nrfx_twim.c 40 0.86%
│ └── m_cb 40 0.86%
└── ZEPHYR_BASE 1701 36.68%
├── arch 5 0.11%
│ └── arm 5 0.11%
│ └── core 5 0.11%
│ ├── mpu 1 0.02%
│ │ └── arm_mpu.c 1 0.02%
│ │ └── static_regions_num 1 0.02%
│ └── tls.c 4 0.09%
│ └── z_arm_tls_ptr 4 0.09%
├── drivers 258 5.56%
│ ├── ... ... ...%
========================================================================================
4637
Build Target: rom_report
========================
List all compiled objects and their ROM usage in a tabular form with bytes
per symbol and the percentage it uses. The data is grouped based on the file
system location of the object in the tree and the file containing the symbol.
Use the ``rom_report`` target with your board, as in the following example.
.. zephyr-app-commands::
:tool: all
:app: samples/hello_world
:board: reel_board
:goals: rom_report
These commands will generate something similar to the output below::
Path Size %
========================================================================================
Root 21652 100.00%
├── ... ... ...%
└── ZEPHYR_BASE 13378 61.79%
├── arch 1718 7.93%
│ └── arm 1718 7.93%
│ └── core 1718 7.93%
│ ├── cortex_m 1020 4.71%
│ │ ├── fault.c 620 2.86%
│ │ │ ├── bus_fault.constprop.0 108 0.50%
│ │ │ ├── mem_manage_fault.constprop.0 120 0.55%
│ │ │ ├── usage_fault.constprop.0 84 0.39%
│ │ │ ├── z_arm_fault 292 1.35%
│ │ │ └── z_arm_fault_init 16 0.07%
│ │ ├── ... ... ...%
├── boards 32 0.15%
│ └── arm 32 0.15%
│ └── reel_board 32 0.15%
│ └── board.c 32 0.15%
│ ├── __init_board_reel_board_init 8 0.04%
│ └── board_reel_board_init 24 0.11%
├── build 194 0.90%
│ └── zephyr 194 0.90%
│ ├── isr_tables.c 192 0.89%
│ │ └── _irq_vector_table 192 0.89%
│ └── misc 2 0.01%
│ └── generated 2 0.01%
│ └── configs.c 2 0.01%
│ └── _ConfigAbsSyms 2 0.01%
├── drivers 6162 28.46%
│ ├── ... ... ...%
========================================================================================
21652
Build Target: puncover
======================
This target uses a third-party tool called puncover which can be found at
https://github.com/HBehrens/puncover. When this target is built, it will
launch a local web server which will allow you to open a web client and browse
the files and view their ROM, RAM, and stack usage.
Before you can use this
target, install the puncover Python module::
pip3 install git+https://github.com/HBehrens/puncover --user
.. warning::
This is a third-party tool that might or might not be working at any given
time. Please check the GitHub issues, and report new problems to the
project maintainer.
After you installed the Python module, use ``puncover`` target with your board,
as in the following example.
.. zephyr-app-commands::
:tool: all
:app: samples/hello_world
:board: reel_board
:goals: puncover
To view worst-case stack usage analysis, build this with the
:kconfig:option:`CONFIG_STACK_USAGE` enabled.
.. zephyr-app-commands::
:tool: all
:app: samples/hello_world
:board: reel_board
:goals: puncover
:gen-args: -DCONFIG_STACK_USAGE=y
.. _data_structures:
Data Structures
****************
Build Target: pahole
=====================
Poke-a-hole (pahole) is an object-file analysis tool to find the size of
the data structures, and the holes caused due to aligning the data
elements to the word-size of the CPU by the compiler.
Poke-a-hole (pahole) must be installed prior to using this target. It can be
obtained from https://git.kernel.org/pub/scm/devel/pahole/pahole.git and is
available in the dwarves package in both fedora and ubuntu::
sudo apt-get install dwarves
Alternatively, you can get it from fedora::
sudo dnf install dwarves
After you installed the package, use ``pahole`` target with your board,
as in the following example.
.. zephyr-app-commands::
:tool: all
:app: samples/hello_world
:board: reel_board
:goals: pahole
Pahole will generate something similar to the output below in the console::
/* Used at: zephyr/isr_tables.c */
/* <80> ../include/sw_isr_table.h:30 */
struct _isr_table_entry {
void * arg; /* 0 4 */
void (*isr)(void *); /* 4 4 */
/* size: 8, cachelines: 1, members: 2 */
/* last cacheline: 8 bytes */
};
/* Used at: zephyr/isr_tables.c */
/* <eb> ../include/arch/arm/aarch32/cortex_m/mpu/arm_mpu_v7m.h:134 */
struct arm_mpu_region_attr {
uint32_t rasr; /* 0 4 */
/* size: 4, cachelines: 1, members: 1 */
/* last cacheline: 4 bytes */
};
/* Used at: zephyr/isr_tables.c */
/* <112> ../include/arch/arm/aarch32/cortex_m/mpu/arm_mpu.h:24 */
struct arm_mpu_region {
uint32_t base; /* 0 4 */
const char * name; /* 4 4 */
arm_mpu_region_attr_t attr; /* 8 4 */
/* size: 12, cachelines: 1, members: 3 */
/* last cacheline: 12 bytes */
};
...
...